ERG immunohistochemistry and clinicopathologic characteristics in Korean prostate adenocarcinoma patients

A cross-sectional study of ERG expression and the relationship with clinicopathological features of Prostate cancer in Southwestern Uganda

BACKGROUND

Prostate cancer is the leading cause of cancer-related death and the second most commonly diagnosed cancer among men in Uganda and most countries in Sub-Saharan Africa (SSA). The TMPRSS2-ERG fusion gene is the most common genetic alteration seen among prostate cancer patients. There are several contradicting reports about the association of ERG protein with poor prognosis, high PSA, and Gleason score. This study determined the prevalence of ERG expression and the relationship with PSA, Gleason score, and Age of prostate cancer patients in Southwestern Uganda.

METHODS

We reviewed 130 archived prostate biopsy (needle and TURP) specimens from patients of age ≥ 50 years who had a histological diagnosis of prostate cancer. We obtained their biodata, and preoperative PSA, from the archived records. We did Immunohistochemistry (IHC) to determine the prevalence of ERG expression.

RESULTS

The mean patient age in our study was 74.64 ± 10.19 years. Pre-operative PSA levels had been done for 79.2% of the participants. Most cancers (58.46%) were of high grade (grade group 3-5). ERG expression prevalence was 75.4% and its expression was independent of age, re-operative PSA, and Gleason score.

CONCLUSION

There is a significantly higher prevalence of ERG expression in our study compared to what is reported in other African-based studies. The expression of the ERG is independent of age, Gleason score, and serum PSA levels. A high proportion of our prostate cancer has high-grade disease at the time of diagnosis.

The relevance of ERG immunoexpression intensity for prostatic adenocarcinoma in radical prostatectomy of 635 samples

Prostate cancer is the world's most frequently diagnosed malignancy in men. Recent work suggests that patients with high ERG expression intensity are significantly more likely to develop biochemical relapse and metastasis, and die of prostate cancer. The objective of this study was to determine the relationship between the intensity of ERG protein expression and the staging of prostate cancer and the formation of metastases in 635 samples. A retrospective cohort analysis was performed using immunohistochemistry reactions in tissue microarray samples taken from non-neoplastic and neoplastic prostate tissue from patients who underwent radical prostatectomies at a reference hospital from 2009 to 2016. For the ERG marker analysis, the samples were scored for the presence or absence of nuclear signals. Weak, moderate, or strong intensity of the nuclei of the observable tumor cells was considered to be positive markers. All told, 635 samples were evaluated, and the ERG expression was inconclusive in 9% of cases, while 30% were positive and 61% were negative. Of the samples with positive result: 25.8% were weak and focal, 53.2% were moderate, and 21% were strong. Finally, 21% of the cases with a positive ERG had a high Gleason score. Metastasis was detected in 41% of the patients who were ERG positive, and of these, the majority had moderate marking and were aged older than 60 years, although there was no statistically significant difference between the older and younger age groups. Patients with moderate to strong ERG staining had higher staging compared to the others, and no increase in metastasis was detected in patients with more intense ERG expression. More studies should be carried out to corroborate these results and to reach a consensus on the intensity and scoring of the expression levels of ERG markers.

Prevalence and clinical application of TMPRSS2-ERG fusion in Asian prostate cancer patients: a large-sample study in Chinese people and a systematic review

Fusion between the transmembrane protease serine 2 and v-ets erythroblastosis virus E26 oncogene homolog (TMPRSS2-ERG fusion) is a common genetic alteration in prostate cancer among Western populations and has been suggested as playing a role in tumorigenesis and progression of prostate cancer. However, the prevalence of TMPRSS2-ERG fusion differs among different ethnic groups, and contradictory results have been reported in Asian patients. We aim to evaluate the prevalence and significance of TMPRSS2-ERG fusion as a molecular subtyping and prognosis indicator of prostate cancer in Asians. We identified the fusion status in 669 samples from prostate biopsy and radical prostatectomy by fluorescence in situ hybridization and/or immunohistochemistry in China. We examined the association of TMPRSS2-ERG fusion with clinicopathological characteristics and biochemical recurrence by Chi-square test and Kaplan–Meier analysis. Finally, a systematic review was performed to investigate the positive rate of the fusion in Asian prostate cancer patients. McNemar's test was employed to compare the positive rates of TMPRSS2-ERG fusion detected using different methods. The positive rates of TMPRSS2-ERG fusion were 16% in our samples and 27% in Asian patients. In our samples, 9.4% and 19.3% of cases were recognized as fusion positive by fluorescence in situ hybridization and immunohistochemistry, respectively. No significant association between the fusion and clinical parameters was observed. TMPRSS2-ERG fusion is not a frequent genomic alteration among Asian prostate cancer patients and has limited significance in clinical practices in China. Besides ethnic difference, detection methods potentially influence the results showing a positive rate of TMPRSS2-ERG fusion.

Application and Pitfalls of Immunohistochemistry in Diagnosis of Challenging Genitourinary Cases

CONTEXT.—

Immunohistochemistry (IHC) has become increasingly important in the evaluation of pathologic conditions in the genitourinary (GU) organs. In addition to careful evaluation of hematoxylin-eosin sections and generation of a differential diagnosis, choosing the optimal panel of IHC markers becomes even more important when the biopsy material is very limited. The following summary of our experience supplemented with relevant literature review exemplifies how to use IHC to facilitate pathologic diagnosis in the GU system.

OBJECTIVE.—

To describe our experience with the most common immunohistochemical markers used in GU pathology.

DATA SOURCES.—

Institutional experience and literature search comprise our data sources.

CONCLUSIONS.—

Application of IHC provides enormous benefits to the interpretation of GU pathologic conditions, including benign and malignant lesions. However, both insufficient and excessive types of use of IHC, as well as incorrect interpretations in common and rare GU conditions, could present pitfalls in diagnosis.

The expression profile and heterogeneity analysis of ERG in 633 consecutive prostate cancers from a single center

BACKGROUND

Overexpression of ERG protein resulting from TMPRSS2:ERG rearrangement is highly specific for prostate cancer (PCa). However, the biological function of this fusion protein and its relationship with clinicopathological features still remain controversial.

METHOD

In this study, we evaluated ERG protein expression/gene rearrangement and heterogeneity by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) in a cohort of 633 consecutive PCa initially diagnosed by core-needle biopsy in the West China Hospital.

RESULT

Overall, ERG protein expression was detected in 16.7% (106 of 633) cases, and frequently observed in PCa patients less than 60 years of age (31.9% vs 15.5%, P = 0.004) and in PCa with Gleason score less than 8 (20.0% vs 13.4%, P = 0.027), but infrequently observed in cases with intraductal carcinoma of the prostate (IDC-P) (10.0% vs 18.6%, P = 0.012). Follow-up analysis found that patients who progressed to castration-resistant prostate cancer (CRPC) have a lower frequency of ERG protein expression at initial biopsies compared to androgen deprivation therapy (ADT)-sensitive cases (14.1% vs 23.5%, P = 0.042), but Kaplan-Meier curve showed that ERG protein expression was not an independent prognostic marker. Of all the 106 ERG-positive cases, eight cases (7.5%) exhibited heterogeneous expression of ERG protein, in which ERG was only positive in tumors with Gleason pattern 3, but negative in Gleason pattern 4. The FISH analysis was consistent with IHC in six of these cases. In the other two cases, ERG rearrangement was detected in tumors with both Gleason pattern 3 and 4 by FISH, despite the negative protein expression in Gleason pattern 4. In case 1, a repeated biopsy was performed when the disease progressed to CRPC, and no ERG-positive cells were identified neither by IHC nor FISH.

CONCLUSION

This was by far the largest series of ERG expression and heterogeneity analysis in Chinese PCa. The ERG rearrangement seemed to be frequently expressed in patients with relatively younger age and lower Gleason score and infrequently expressed in PCa with the IDC-P. PCa with positive ERG were less frequently to progress to CRPC, but there was no prognostic significance of ERG expression. In heterogeneous cases, ERG protein was detectable only in tumors with Gleason pattern 3 but not in pattern 4. Tumor cells with positive ERG expression/rearrangement seemed easily response to ADT.

The Role of Immunohistochemical Analysis as a Tool for the Diagnosis, Prognostic Evaluation and Treatment of Prostate Cancer: A Systematic Review of the Literature

Background: Prostate cancer (PCa) is a heterogeneous disease that lends itself toward numerous therapeutic options depending on its risk stratification. One of the greatest challenges in PCa urologic practice is to select patients who should be referred for biopsy and, for those patients who are diagnosed with cancer, to differentiate between patients with indolent disease from those with an unfavorable prognosis and, to determine ideal patient management and avoid unnecessary interventions. Accordingly, there is a growing body of literature reporting immunohistochemical studies with the objective of determining a prostate cancer prognosis. Among the most frequent biomarkers studied are Ki-67, p53, PTEN, MYC, and ERG. Based on these findings, we systematically reviewed articles that assessed the role of these main prognostic markers in prostate cancer.

Methods: Consistent with PRISMA guidelines, we performed a systematic literature search throughout the Web of Science and PubMed Medline databases. We considered all types of studies evaluating the role of Ki-67, p53, PTEN, MYC, and ERG immunohistochemical analysis in prostate cancer until July 2017.

Results: We identified 361 articles, 44 of which were summarized in this review. Diagnostically, no single immunohistochemical marker was able to define a tumor as benign or malignant. Prognostically, Ki-67, p53, and MYC were related to the tumor grade given by Gleason score and to the tumor stage (higher levels related to higher tumor grade). Furthermore, Ki-67 was also related to higher PSA levels, shorter disease-free intervals and shorter tumor-specific survival; the latter was also related to p53. The loss of PTEN protein expression showed a higher association with biochemical recurrence and with a worse prognosis, beyond that predicted by the Gleason score and tumor stage. ERG staining also showed a strong association with biochemical recurrence.

Conclusion: There are several studies relating immunohistochemical markers with clinical-laboratorial outcomes in prostate cancer, the most frequent being Ki-67, p53, ERG, PTEN, and MYC. However, none of these markers have been validated by literary consensus to be routinely applied in medical practice.

Intrafocal heterogeneity of ERG protein expression and gene fusion pattern in prostate cancer

BACKGROUND

Prostate cancer is considered to be highly heterogeneous, with various morphologic features and biologic behaviors. The TMPRSS2-ERG gene fusion is the most frequently observed genetic aberration in prostate cancer. The aim of this study was to elucidate the intrafocal heterogeneity of ERG gene fusion status.

METHODS

ERG immunohistochemistry (IHC) was performed in samples from 168 prostate cancer patients who had undergone radical prostatectomy, and 40 cases showing ERG-positive IHC staining were selected for tissue microarray (TMA) construction. Two to six representative cores were selected from each tumor focus. In the cases with heterogeneous ERG IHC staining intensity, the areas showing different intensities were separately selected. Using the TMA blocks, IHC and fluorescence in situ hybridization (FISH) were conducted to evaluate the heterogeneity of ERG protein expression and ERG fusion gene patterns, respectively, in a single tumor focus. Heterogeneity of ERG IHC staining was defined as the simultaneous presence of negative and positive cores in the same tumor focus. Heterogeneity of ERG FISH was defined by the presence of cores with positive and negative FISH signals or cores with break-apart and interstitial deletion FISH signals in the same tumor focus.

RESULTS

A total of 202 TMA cores were isolated from 40 ERG-positive cases. Of the 202 total cores, 19 were negative for ERG IHC staining, and 46 showed 1+, 52 showed 2+, and 85 showed 3+ ERG staining intensity. Eleven cores were negative for ERG FISH signal, 119 cores showed ERG break-apart FISH signals, and the remaining 72 cores revealed interstitial deletion. Intrafocal heterogeneity of ERG IHC staining was found in 20% (8/40) of cases, and intrafocal heterogeneity of ERG gene fusion pattern was found in 32.5% (13/40) of cases.

CONCLUSIONS

In summary, this study showed significantly frequent intrafocal heterogeneity of ERG protein expression, gene fusion status and fusion pattern. This heterogeneity can be caused by the development of subclones during cancer progression or the intermingling of different tumors.

Ethnicity and ERG frequency in prostate cancer

Emerging observations emphasize a distinct biology of prostate cancer among men of different ethnicities and races, as demonstrated by remarkable differences in the frequency of ERG oncogenic activation, one of the most common and widely studied prostate cancer driver genes. Worldwide assessment of ERG alterations frequencies show consistent trends, with men of European ancestry having the highest rates of alteration and men of African or Asian ancestries having considerably lower alteration rates. However, data must be interpreted cautiously, owing to variations in assay platforms and specimen types, as well as ethnic and geographical classifications. Many opportunities and challenges remain in assessing cancer-associated molecular alterations at a global level, and these need to be addressed in order to realize the true potential of precision medicine for all cancer patients.

Diverse Immunoprofile of Ductal Adenocarcinoma of the Prostate with an Emphasis on the Prognostic Factors

BACKGROUND

Ductal adenocarcinoma (DAC) of the prostate is an uncommon histologic subtype whose prognostic factors and immunoprofile have not been fully defined.

METHODS

To define its prognostic factors and immunoprofile, the clinicopathological features, including biochemical recurrence (BCR), of 61 cases of DAC were analyzed. Immunohistochemistry was performed on tissue microarray constructs to assess the expression of prostate cancer-related and mammalian target of rapamycin (mTOR) signaling-related proteins.

RESULTS

During the median follow-up period of 19.3 months, BCR occurred in 26 cases (42.6%). DAC demonstrated a wide expression range of prostate cancer-related proteins, including nine cases (14.8%) that were totally negative for pan-cytokeratin (PanCK) immunostaining. The mTOR signaling-related proteins also showed diverse expression. On univariate analysis, BCR was associated with high preoperative serum levels of prostate-specific antigen (PSA), large tumor volume, predominant ductal component, high Gleason score (GS), comedo-necrosis, high tumor stage (pT), lymphovascular invasion, and positive surgical margin. High expressions of phospho-mTOR (p-mTOR) as well as low expressions of PSA, phospho-S6 ribosomal protein (pS6) and PanCK were associated with BCR. On multivariable analysis, GS, pT, and immunohistochemical expressions of PanCK and p-mTOR remained independent prognostic factors for BCR.

CONCLUSIONS

These results suggest GS, pT, and immunohistochemical expressions of PanCK and p-mTOR as independent prognostic factors for BCR in DAC. Since DAC showed diverse expression of prostate cancer-related proteins, this should be recognized in interpreting the immunoprofile of DAC. The diverse expression of mTOR-related proteins implicates their potential utility as predictive markers for mTOR targeted therapy.

Cancer Prognosis Defined by the Combined Analysis of 8q, PTEN and ERG

Overtreatment is a major concern in men diagnosed with prostate cancer. The aim of this study was to evaluate the combined prognostic role of three frequent molecular alterations in prostate cancer, namely relative 8q gain, ERG overexpression, and loss of PTEN expression, in a series of 136 patients with prostate cancer treated with prostatectomy and with a long follow-up. Fluorescent in situ hybridization was used to detect the relative copy number of 8q and immunohistochemistry was used for quantitative assessment of ERG and PTEN expression. During a median follow-up period of 117.8 months, 66 (49%) patients had disease recurrence. Relative 8q gain, ERG overexpression, and loss of PTEN expression were observed in 18%, 56%, and 33% of the cases, respectively. No association with patient recurrence-free survival was found for relative 8q gain or ERG overexpression on their own, whereas loss of PTEN expression was associated with worse recurrence-free survival (P=.006). Interestingly, in the subgroup of patients with normal PTEN expression, we found that the combined relative 8q gain/ERG overexpression is associated with high risk of recurrence (P=.008), suggesting that alternative mechanisms exist for progression into clinically aggressive disease. Additionally, in intermediate-risk patients with normal PTEN expression in their tumors, the combination of 8q gain/ERG overexpression was associated with a poor recurrence-free survival (P<.001), thus indicating independent prognostic value. This study shows that the combined analysis of 8q, ERG and PTEN contributes to an improved clinical outcome stratification of prostate cancer patients treated with radical prostatectomy.

Correlation of ERG immunohistochemistry with molecular detection of TMPRSS2-ERG gene fusion

Aims

TMPRSS2/E26 transformation-specific (ETS) family gene fusion in prostate carcinoma (PCa) can be detected by several methods including immunohistochemistry (IHC) for ETS-related gene (ERG), the diagnostic utility of which has not been clearly defined.

Methods

We explored TMPRSS2-ERG gene rearrangement status in 132 patients with PCa with four detection methods including fluorescence in situ hybridisation for TMPRSS2-ERG fusion, real-time reverse transcription PCR (RT-qPCR) for ERG and TMPRSS-ERG fusion transcript mRNA and IHC for ERG.

Results

Concordant results were found in 126 cases for the four detection methods and the remaining six cases showed discrepancy in one method: two cases in IHC, three cases in RT-qPCR for ERG and one case in RT-qPCR for fusion transcript. In discordant cases, the majority results were determined as final fusion status. Analysis of discrepancy cases for ERG IHC showed that weak immunoreactivity for ERG should be regarded as equivocal and that even strong immunoreactivity can be false positive. The overall incidence of TMPRSS-ERG gene fusion was 24%.

Conclusions

ERG IHC is a useful surrogate test for the detection of TMPRSS2-ERG gene fusion, but it needs to be interpreted with caution and definite judgement should not be based on IHC alone. A relatively low incidence of TMPRSS2-ERG gene fusion was demonstrated in this Korean cohort.

Overexpression of ERG and Wild-Type PTEN Are Associated with Favorable Clinical Prognosis and Low Biochemical Recurrence in Prostate Cancer

OBJECTIVES

The aim of this study was to investigate the expression of two commonly altered genes ERG and PTEN in prostate cancer (PC) and evaluate their prognostic significance. Despite conflicting published results, TMPRSS2-ERG gene fusion and PTEN loss are generally considered unfavorable markers for PC progression.

MATERIALS AND METHODS

Of the 762 prostatic adenocarcinoma specimens obtained from radical prostatectomy, 613 without neoadjuvant hormone therapy were included in tissue microarrays for quantitatively assessment of ERG and PTEN expression via immunohistochemistry. Statistical analysis of the association between such expression and clinicopathological parameters, including clinical prognosis, was performed with a p-value of <0.05 considered significant.

RESULTS

During a median follow-up period of 44.0 months, 132 (21.5%) patients developed biochemical recurrence (BCR). ERG overexpression and PTEN loss were observed in 145 (23.7%) and 253 (41.3%) cases, respectively. BCR-free survival was significantly better in patients with ERG overexpression (p=0.005), but unfavorable among those with PTEN loss (p=0.142). Sub-group analysis revealed that patients with PTEN loss and negative ERG expression had the worst BCR-free survival outcome (p=0.021). Furthermore, multivariate analysis identified prostate-specific antigen level (≥10 ng/mL), Gleason score (>6), pathologic T stage (≥T3), positive surgical margin, and extraprostatic capsule extension as significant risk factors for BCR (p<0.05).

CONCLUSIONS

Our results indicated that ERG overexpression was associated with favorable BCR-free survival after radical prostatectomy for PC, whereas PTEN loss was with unfavorable outcomes.

Expression of c-MET in Invasive Meningioma

Background:

Meningiomas show high recurrence rates even after curative tumor removal. The invasiveness of meningiomas may contribute to their high recurrence rates. Recently, c-MET and hepatocyte growth factor (HGF) have been reported to be involved in cancer invasion.

Methods:

We examined the immunohistochemical expression of c-MET and HGF in 100 cases of patients with meningiomas who have undergone complete tumor removal.

Results:

c-MET^-High and HGFHigh were found in 17% and 13% of meningiomas, respectively. Brain invasion was observed in 17.6% of c-MET^-High meningiomas, but in only 2.4% of c-MET^-Low meningiomas (p=.033). Bone/soft tissue invasion was observed in 23.5% of c-MET^-High meningiomas and in 9.6% of c-MET^-Low meningiomas (p=.119). HGF^-High did not show statistical association with brain invasion or bone/soft tissue invasion. c-MET^-High demonstrated shorter recurrence-free survival (RFS, 93.5±8.2 months vs 96.1±1.9 months); however, this difference was not statistically significant (p=.139). There was no association of HGF^-High with RFS.

Conclusions:

This study demonstrates that c- MET^-High is associated with brain invasion of meningiomas, and that c-MET expression may be a useful predictive marker for meningioma recurrence. Patients with invasive meningiomas with high expressions of c-MET may be good candidates for targeted therapy using c-MET inhibitors.

ERG oncoprotein expression in prostate carcinoma patients of different ethnicities

Overexpression of the erythroblast transformation-specific-related gene (ERG) oncoprotein due to transmembrane protease, serine 2 (TMPRSS2)-ERG fusion, the most prevalent genomic alteration in prostate cancer (CaP), is more frequently observed among Caucasian patients compared to patients of African or Asian descent. To the best of our knowledge, this is the first study to investigate the prevalence of ERG alterations in a multiethnic cohort of CaP patients. A total of 191 formalin-fixed paraffin-embedded sections of transrectal ultrasound-guided prostate biopsy specimens, collected from 120 patients treated at the Sime Darby Medical Centre, Subang Jaya, Malaysia, were analyzed for ERG protein expression by immunohistochemistry using the anti-ERG monoclonal antibody 9FY as a surrogate for the detection of ERG fusion events. The overall frequency of ERG protein expression in the population evaluated in this study was 39.2%. Although seemingly similar to rates reported in other Asian communities, the expression of ERG was distinct amongst different ethnic groups (P=0.004). Malaysian Indian (MI) patients exhibited exceedingly high expression of ERG in their tumors, almost doubling that of Malaysian Chinese (MC) patients, whereas ERG expression was very low amongst Malay patients (12.5%). When collectively analyzing data, we observed a significant correlation between younger patients and higher ERG expression (P=0.04). The prevalence of ERG expression was significantly different amongst CaP patients of different ethnicities. The higher number of ERG-expressing tumors among MI patients suggested that the TMPRSS2-ERG fusion may be particularly important in the pathogenesis of CaP amongst this group of patients. Furthermore, the more frequent expression of ERG among the younger patients analyzed suggested an involvement of ERG in the early onset of CaP. The results of this study underline the value of using ERG status to better understand the differences in the etiology of CaP initiation and progression between ethnic groups.

ETV1 directs androgen metabolism and confers aggressive prostate cancer in targeted mice and patients

Distinguishing aggressive from indolent disease and developing effective therapy for advanced disease are the major challenges in prostate cancer research. Chromosomal rearrangements involving ETS transcription factors, such as ERG and ETV1, occur frequently in prostate cancer. How they contribute to tumorigenesis and whether they play similar or distinct in vivo roles remain elusive. Here we show that in mice with ERG or ETV1 targeted to the endogenous Tmprss2 locus, either factor cooperated with loss of a single copy of Pten, leading to localized cancer, but only ETV1 appeared to support development of invasive adenocarcinoma under the background of full Pten loss. Mechanistic studies demonstrated that ERG and ETV1 control a common transcriptional network but largely in an opposing fashion. In particular, while ERG negatively regulates the androgen receptor (AR) transcriptional program, ETV1 cooperates with AR signaling by favoring activation of the AR transcriptional program. Furthermore, we found that ETV1 expression, but not that of ERG, promotes autonomous testosterone production. Last, we confirmed the association of an ETV1 expression signature with aggressive disease and poorer outcome in patient data. The distinct biology of ETV1-associated prostate cancer suggests that this disease class may require new therapies directed to underlying programs controlled by ETV1.